Basf Magnetics Gmbh

Basf Corporation

Emtec Magnetics Gmbh

Rudi Lehnert

Manfred Ohlinger

Ekkehard Schwab

Helmut Jakusch

Ronald J Veitch

Harald Jachow

Helmut Auweter

Norbert Mueller

August Lehner

Werner Lenz

Albert Kohl

Norbert Schneider

Rainer Feser

Peter Heilmann

Michael Bobrich

Michael W Mueller

Volker Koch

Reinhard Koerner

Erich Hoffmann

Reinhard K Orner

Bernd H Oppner

Werner H&uuml;bner

Described are tape-type magnetic recording media (I) including a non-magnetic substrate (III), at least one film applied to the substrate and, in at least one of these films, an inorganic acicular pigment (II) suitable for use as a supporting pigment, the ratio of the mean length to the mean diameter of the pigment (II) being at least 3 and the mean modulus of elasticity of the films being not less than 15 GPa in the longitudinal direction of the tape-type recording medium (I).

Magnetic recording media

A finely divided acicular CrO.sub.2 modified with iron, tellurium and/or antimony and having a high coercive force possesses improved heat stability of the residual induction and a relatively narrow distribution of the particle size and of the coercive force. This CrO.sub.2 pigment is obtained by a method in which the iron compound used for the modification is iron oxalate, which is employed in an amount of 1-10% by weight, based on the theoretical CrO.sub.2 yield.

Finely divided acicular magnetic modified chromium dioxide

A magnetic recording medium comprising a nonmagnetic substrate and at least one magnetic layer applied thereon and containing an acicular chromium dioxide uniformly distributed in a polymeric binder and additives and having a coercive force of at least 60 kA/m, a mean particle length of the chromium dioxide of less than 300 nm, whose factor HD according to the formula ##EQU1## where KT is the coercive force of the magnetic layer in [kA/m], measured in an external field of 380 kA/m, L is the mean particle length and .DELTA.L is the range of the particle size distribution, determined from the numerical distribution of the particle length, both measured in [nm], is greater than 1.85, and a process for the preparation of this chromium dioxide.

Process for preparing modified chromium dioxide

An acicular, ferromagnetic material which has a high coercive force and essentially consists of iron-containing chromium dioxide is prepared by thermal decomposition of hydrated chromium(III) chromate under superatmospheric pressure.

Process for preparing acicular ferromagnetic material consisting

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Ludwigshafen, Germany

Rudi Lehnert